The present invention relates to railway trucks and, more particularly, to a three axle railway truck.
Increased utilization of stacked container cars has lead to the realization that existing two axle freight car truck designs do not have adequate capacity to accommodate two or more containers loaded to their maximum allowable capacity. An alternative truck design, which solves many of the capacity problems, is the three axle truck. However, existing designs of three axle trucks present several problems relative to their accommodation under the railway car body. These designs of three axle trucks (shown generally in FIG. 1 of the drawings) have a centrally located centerplate on a single, large bolster casting, which in the case of well type stacked container cars, complicates car body construction requiring extensive overhang beyond the well. This not only increases the strength requirements for this portion of the car structure, but also adds weight to the car body. Such prior art three axle truck designs have four sideframes (two per side) which are joined over the center axle. The massive single piece bolster is supported by spring groups at each of the four sideframes wherein ends of the bolster extend. The single centerplate is flanked by raised side bearing pads all of which are positioned over the center axle. Such three axle truck designs are difficult and expensive to cast due to the overall size, complexity and weight of the bolsters. Alignment of the four bolster ends requires extensive gauging procedures and adjustment using plates and welding. The rigidity of the bolster with respect to the four ends results in a deterioration in the trucks equalization capabilities, a condition which contributes to derailment. The complexity of the brake rigging is a further problem and creates a significant maintenance item.
The present invention provides a three axle truck with the necessary load carrying capacity for the containerized applications and other uses. The truck is equipped with two bolsters each having a centerplate and side bearing supports. The centerplate and side bearing supports are located longitudinally on the truck somewhat near the end axle wheelsets to help decrease the length of car body overhang required to interface with the truck and to distribute the load to the axles so as to not overload the center axle. Further, articulated connectors are utilized to join the car body to the truck. A typical articulated connector is shown in U.S. Pat. No. 4,593,829, assigned to the assignee of the present case. In the particular arrangement of the present invention, a simulated car body center sill structure is utilized to join the two connectors at each bolster. This center sill passes over the center axle of the truck and provides a load path for the longitudinal train forces. To simplify car and truck assembly, the articulated connector's female connection is attached to the car body and the male connection to the simulated center sill. Other combinations of connections in car bodies are possible to accommodate specific car construction needs. Further, the simulated center sill can be replaced by any structure which can provide the longitudinal load path between the centerplates.
Each car body centerplate rests on individual truck bolsters, each with its own set of load springs and truck snubbing elements in the sideframe bolster opening. The truck bolster structure is simplified from the single bolster structure of the prior art by eliminating the need to carry the load at a central point. Further, the articulated connection and center sill are adapted to carry the buff or compression and draft or pulling train forces.